I'm curious on how they adjust a competitors time if someone is slowed down by an accident ahead.

IE: car A goes and has no issues. gets a time of 30 minutes.
car B goes and crashes and ends up scattering debris all over the course, as well as landing in the middle of the road.
car C comes along, and is slowed either by debris, or by the car still in the way.

does car C get any sort of adjustment, or do they just get to suck it up and hope they can make up the loss?

I do know they set off with a few minutes between them, but something like this has to have happened at some point.